JPS63317545A - Epoxy polymer composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy polymer composition loadable with large quantity of filler without causing settling over a long period, by compounding a filler having small average particle diameter and a filler having large average particle diameter to a hardener component in a two-pack type epoxy polymer composition. CONSTITUTION:The objective epoxy polymer composition is a two-pack type epoxy polymer composition containing an epoxy polymer (a liquid polymer including epi-bis-type or cycloaliphatic epoxy polymer, etc.), an acid anhydride hardener (a liquid hardener containing methyltetrahydrophthalic anhydride, etc.) and a filler (preferably containing fused silica and/or crystalline silica). In the above composition, the filler is dividedly compounded to the polymer component and the hardener component and the filler compounded to the hardener component is a mixture of a filler having large average particle diameter (preferably an average particle diameter of 5-20mum) and a filler having small particle diameter (preferably <2mum) at a ratio of preferably 85/15-75/25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a two-component epoxy resin composition used as an adhesive, a casting material, etc. for electrical and electronic applications.

[Background technology]

Epoxy resins have excellent electrical insulation properties, adhesive properties, mechanical strength, heat resistance, moisture resistance, chemical resistance, etc., and have therefore been useful in many fields including electrical and electronic fields. On the other hand, with the remarkable development of the electronics industry in recent years, electronic parts have come to be used in harsher environments, so epoxy resins are also required to have higher heat resistance than before. In addition, materials with a low coefficient of linear expansion are desired in order to prevent cracks from occurring and changes in properties due to thermal history. In response to this, by adding a large amount of filler to the epoxy resin,
We are working on improvements such as lowering the coefficient of linear expansion and increasing heat resistance and DHJi impact resistance.

To use the epoxy resin composition, the resin component called the base resin and the amine or acid anhydride curing agent component are stored separately, and before use, both components are mixed in a predetermined ratio and defoamed. is common. In this case, a filler is usually blended into the main ingredient, and if necessary, a camping agent, an antifoaming agent, a coloring agent, etc. are blended, and a curing accelerator is blended into the curing agent. The reason for blending the filler into the main ingredient is to avoid filler sedimentation during storage. Sedimentation of the filler causes the ingredients to become non-uniform, and if left for a long time, it aggregates at the bottom to form a solid layer (this phenomenon is called caking due to sedimentation), making it impossible to use it in the future. turn into. Bisphenol A type epoxy resin is often used, but the viscosity of this resin is 5,000 to tens of thousands of cps, compared to the viscosity of a general liquid acid anhydride curing agent of several tens of cps. In comparison, it has a significantly higher viscosity. Filler sedimentation is less likely to occur in a high viscosity resin than in a low viscosity curing agent.

However, incorporating a large amount of filler especially for the purpose of lowering the coefficient of linear expansion poses the following problems. In other words, the viscosity of the main ingredient becomes too high due to filler blending, making it impossible to knead, or even if kneading is possible, it is very difficult to mix and stir the curing agent evenly. It becomes.

Therefore, there is a strong need for a method that requires blending a part of the filler with the curing agent component and that does not cause caking due to sedimentation or change the viscosity or thixotropy, but no satisfactory method has yet been found. Not yet.

[Purpose of the invention]

In view of the above circumstances, in order to prevent settling for a long period of time and to avoid affecting the viscosity and fluidity of the compound, a silica-based filler is added to a general liquid acid anhydride-based curing agent component. The object of the present invention is to provide an epoxy resin composition containing a large amount of polycarbonate and having a low coefficient of linear expansion after curing.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides an epoxy resin,
In a two-component epoxy resin composition that contains an acid anhydride curing agent and a filler, and in which the resin component and the curing agent component are stored separately, the filler is mixed separately into the resin component and the curing agent component. , and the filler added to the curing agent component is
The present invention will be described in detail below, focusing on an epoxy resin composition characterized in that it is composed of particles with a small average particle size and particles with a large average particle size.

As the epoxy resin, those commonly used for such purposes can be used. That is, shrimp-bis type epoxy resins such as bisphenol A diglycidyl ether and bisphenol F diglycidyl ether, phenol novolac type epoxy resins such as phenol novolac resin glycidyl ether, cresol novolal type epoxy resins such as cresol novolak resin glycidyl ether, These include alicyclic epoxy resins. These can be used alone or in combination. Furthermore, epoxy resins other than these may be used. However, in the present invention, the epoxy resin must be a liquid epoxy resin containing one or more of the above Ebis type or alicyclic type epoxy resins.

Various curing agents can be considered, and among them, acid anhydride curing agents are used in this invention for the purpose of improving electrical insulation. For example, aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, methyltetrahydrophthalic anhydride (MTHPA), methylhexahydrophthalic anhydride (MHHPA) , cyclic aliphatic acid anhydrides such as tetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, methylcyclohexenetetracarboxylic anhydride, pyromellitic anhydride, 5-(
2,5-dioxotetrahydro-3-furanyl)-3-
Examples include methyl-3-cyclohexene-1,2-dicarboxylic anhydride. These can be used alone or in combination. Further, acid anhydride curing agents other than these may also be used. however,
It must be a liquid curing agent containing one or more of the above M T HP A or MHHPA.

Examples of curing accelerators that help the reaction between the epoxy resin and the acid anhydride curing agent include tertiary amines or salts thereof;
Triazoles or their salts, imidazoles or their salts, organic total complex salts, organic acid metal salts, quaternary ammonium salts, phosphines, phosphonium salts, diazabicycloalkenes or their salts, etc., known ones. may be used alone or in combination.

The types of fillers to be added to the main component and curing agent component include general fillers normally used in epoxy resin compositions, such as fused silica, crystalline silica, talc, and calcium carbonate, each alone or Multiple items can be applied together. However, in this invention, various types of mechanical strength and heat resistance are used.

In addition to improving impact resistance, adhesiveness, etc., it is preferable to contain at least one of the above-mentioned fused silica and crystalline silica, especially for the purpose of reducing the coefficient of linear expansion.

The particle sizes of the filler (A) with a large average particle size and the filler (B) with a small average particle size to be blended into the curing agent component are not particularly limited in this invention, but the average particle size of A is 5 to 20 μm, and the average particle size of B is 5 to 20 μm. Preferably, the average particle size is less than 2 μm. Furthermore, B
The average particle size of is less than 1 μm, and 5 μm of
It is more preferable that the amount of particles having a particle size of m or more is within 10% by weight of the total B. If the average particle size of A exceeds 20 μm, or if the average particle size of B exceeds 2 μm, sedimentation of the filler tends to occur;
If it is less than μm, there is a risk that the viscosity and thixotropy of the compound will increase.

The blending ratio of the fillers A and B is not particularly limited in this invention, but the ratio A/B of both is 85/15 to 75.
It is desirable that the value be set to /25. If the proportion of B exceeds 25% by weight of the total of both, the viscosity of the blend will increase and the fluidity will deteriorate; if it is less than 15% by weight, caking due to sedimentation may occur.

In this invention, the filler blended into the curing agent component is
Although the reason for the effect of not settling even after long-term storage is not clear, it can be presumed as follows.

That is, if filler A with a large particle size is used alone, it tends to coagulate and settle together due to van der Waals forces, etc., but when filler A with a large particle size and filler B with a small particle size are used together, It is thought that by forming a packing structure in which these particles are evenly dispersed, small particles prevent collisions between large particles, reduce the attractive force between the particles, and prevent agglomeration. Also, a small particle B pushed away by a large particle
Repulsion of surface charges or increase in entropy occurs between
It can be inferred that it is effective in preventing aggregation. In a coarse dispersion system consisting of particles larger than colloidal particles, the dispersed state is easily broken due to sedimentation or floating of the particles.
Filler A, which is thermodynamically unstable and has a large particle size, tends to settle easily, but its free sedimentation changes to so-called interference sedimentation in which it is interfered with by filler B, which has a small particle size, so the sedimentation rate decreases. It is also possible that there is an effect of decreasing the amount.

Various additives usually added to epoxy resin compositions include:
It can be added in an amount that does not contradict the purpose of the present invention and does not impair the desired effect. Examples of such additives include pigments such as carbon black, red iron oxide, and titanium white, diluents typified by phenyl glycidyl ether, silane coupling agents, leveling agents, antifoaming agents, and ion trapping agents. .

As described above, according to the present invention, the filler is made of a general liquid acid anhydride so that caking due to sedimentation does not occur even during long-term storage and does not affect the viscosity and fluidity of the formulation. It is possible to incorporate it into the system curing agent component. Therefore, in the epoxy resin composition of the present invention containing each of the above-mentioned components, since it can contain a large amount of filler, curing shrinkage is small, linear expansion coefficient after curing is low, and at the same time fluidity is improved. can maintain its quality. This increases heat resistance and impact resistance, and improves adhesion to ceramics, metals, etc. when heated, and at the same time,
Operations such as kneading, mixing, stirring, etc. are easy, and it becomes possible to realize an epoxy resin that is easy to handle.

Next, examples of the present invention will be described together with comparative examples.

(Examples 1 to 52. Comparative Examples 1 to 4) Epi-bis type epoxy resin (EX manufactured by Dainippon Ink Chemical Co., Ltd.)
A4040) 100 parts by weight, 160 parts by weight of fused silica (0 Kikuryumori brand name Y-40, average particle size 8 μm)? A mixture was prepared by blending the following parts.

This was kneaded for 10 minutes at 3000 rpm using Homo Disper (manufactured by Tokushu Kika Kogyo ■) to obtain a main ingredient.

As a curing agent component, methylhexahydrophthalic anhydride (MHHPA, Epiclon B-6 manufactured by Dainippon Ink Chemical
50, acid anhydride equivalent 168), 1 part by weight of octyl salt of curing accelerator diazabicycloundecene (DBU) (San Abro 0 Kiku 5A-102), and the filling shown in Table 1. 150 parts by weight of fused silica or crystalline silica as a material was blended and kneaded in the same manner as for the base ingredient. However, fused silica with an average particle size of 0.9 μm is different from fused silica with an average particle size of 5 μm (Fuselex Y-
No. 60) was crushed using a quartz glass pole in a quartz pot.

The settling properties of the filler in this curing agent component were observed after being left at 25° C. for 3 months.

Mix the base ingredient component/curing agent component in a ratio of 26/24.1 using a spatula, and spread this mixture on an aluminum plate for 120 minutes.
Cure for 1 hour plus 3 hours at 160°C.
An epoxy resin with a filler content of 62% by weight was obtained.

On the other hand, using a Brockfield viscometer SC rotor for the above-mentioned main component/curing agent component mixture before curing,
1) Viscosity ρ1 after rotating at 00 rpm for 30 seconds, standing still for 30 seconds, and further rotating at ioOrpm for 60 seconds, and similarly 1) After rotating at 00 rpm for 30 seconds, standing still for 30 seconds, 10
The viscosity ρ2 was measured after rotating at rpm for 60 seconds. From the obtained viscosity, the thixotropic index was calculated according to the following formula.

Thixoindex = viscosity ρ2/viscosity ρ.

These results are shown in Table 1.

As shown in Table 1, in this example, the amount of filler can be increased to 62% by weight of the entire epoxy resin, and the epoxy resin composition has a thixoscopic index of 1.30 or less and good fluidity. I was able to get it.

〔Effect of the invention〕

The epoxy resin composition of this invention is as described above,
In a two-component epoxy resin composition containing an epoxy resin, an acid anhydride curing agent, and a filler, in which the resin and curing agent components are stored separately, the filler added to the curing agent component has an average particle size of Since it is composed of small and large fillers, even if the amount of filler is large, caking due to sedimentation will not occur due to long-term storage, and the viscosity and fluidity of the compound will not be affected. In this way, the amount of filler is increased, so there is less curing shrinkage and a low coefficient of linear expansion after curing, while maintaining good fluidity.
It is possible to realize an epoxy resin with good heat resistance, impact resistance, adhesiveness, etc.

Claims (2)

[Claims] (1) In a two-component epoxy resin composition containing an epoxy resin, an acid anhydride curing agent, and a filler, in which the resin component and the curing agent component are each stored separately, the filler is the resin component and the curing agent component. An epoxy resin composition characterized in that the filler is separately blended into the curing agent component and the filler is composed of fillers having a small average particle size and fillers having a large average particle size. (2) The filler blended into the curing agent component has an average particle size of 5 to
Consisting of a filler (A) with a diameter of 20 μm and a filler (B) with an average particle size of less than 2 μm, the blending ratio of both A/B = 85/15 ~
75/25, wherein the epoxy resin composition (3) filler is at least one of crystalline silica and fused silica. The epoxy resin composition according to item 2.